The Montgomery County resident who killed his psychiatrist five years ago was taken into custody Friday in connection with the killing of his roommate at a secure state hospital for the mentally ill.

Maryland State Police said that Vitaly Davydov, 24, was taken into custody at the Clifton T. Perkins Hospital in Jessup.

Davydov was to be taken late Friday night for an initial appearance before a court commissioner in the death of David Rico-Noyola, 22, a former Anne Arundel County resident, said Greg Shipley, the police spokesman.

In a statement, police said no motive for the killing of Rico-Noyola had been established. Also unclear was the type of weapon used in the killing.

Police said that based on a preliminary investigation, about 2:30 p.m. Davydov left the room he and the victim shared in a maximum-security wing of the hospital. Police said that Davydov asked a security officer for assistance.

The officer and hospital staff found the victim on the floor of the room, police said. He was bleeding and had head and body wounds, they added. On April 3, 2007, Davydov pleaded guilty in the fatal beating of Rockville psychiatrist Wayne S. Fenton during an office visit. Fenton was a renowned specialist in the treatment of schizophrenia. A judge found Davydov not criminally responsible, the equivalent of legally insane.

The judge concluded that severe mental illness prevented Davydov from realizing that he was committing a crime and ordered him committed to Perkins until he was determined to no longer be dangerous.